A lifting door designed as a fast-running industrial door has, for instance, become known from DE 199 15 376 A1. The door leaf is here designed in the kind of a slatted curtain, wherein the individual slats are connected to one another so as to bend against each other and are guided in lateral guides. The guides each comprise a vertical section and a spiral section, wherein the latter is arranged in the lintel region of the lifting door. The door leaf is guided in the lateral guides by means of guide rollers, wherein their rotational axes coincide with the pivot axes of the individual slats. At the side of the guide rollers which faces away from the door leaf, a collar is further arranged by means of which an indirect positive-locking accommodation of the side edges of the door leaf in the lateral guides exists. This known roller door is characterized by very high movement speeds of up to 4 m/s during opening and closing and by a low-noise and low-energy operation. Moreover, an adequate closure of the door opening is provided thereby.
The sealing of the movement gap between the door leaf and the door opening is effected with the roller door according to DE 199 15 376 A1 by means of lip seals. They are attached to the frames and rest on the two large faces of the door leaf, so that they close the respectively existing movement gap. Although this sealing system has absolutely stood the test in practice, it is deemed to be improvable. In particular, these lip seals are subject to considerable wear since the door leaf slides along them at high movement speed during opening and closing, which results in abrasion especially on the sealing elements. This applies in analogy also to other sealing systems in which, for instance, brush sealing systems are used instead of the lip seals. These sealing elements therefore have to be exchanged at predetermined intervals.
Moreover, such roller doors, as they have been disclosed in DE 199 15 376 A1, are also used for special purposes, for instance, as freezer doors, clean room doors, fire protection doors, as door closures in pharmaceutical companies, or the like. Due to the specific case of use there exists a special need of a reliable and long-lasting sealing of the movement gap between the door leaf and the door opening, wherein this is of particular importance at the outer side of the door.
Furthermore, DE 103 00 302 A1 and U.S. Pat. No. 2,069,665 disclose lifting doors in which the lateral guides are divided such that the vertical section is adapted to be pivoted relative to the lintel section. In the open position of the lifting door the vertical section is inclined to the door opening plane such that it is farther spaced apart therefrom at the upper end of the door opening than at the lower end. In the course of the closure movement of the door leaf, the door leaf then acts on a frame-side actuator, so that the upper ends of the vertical sections are pivoted in the direction of the door opening. Thus, the door leaf then rests on the frames and/or the sealing elements that are possibly arranged there, and closes the gap between the door leaf and the door opening.
A similar construction of a lifting door has been known from U.S. Pat. No. 5,402,841. Here, the door leaf is guided in lateral guides comprising a vertical section and a flat-stretched lintel section which are firmly connected with each other. These guides are mounted to be pivoted about rotational axes at their feet, so that they are adapted to be swiveled as a whole towards the door opening or away from the door opening. In the open position of the lifting door the guides are arranged to be inclined to the door leaf plane such that the upper ends of the vertical sections are again spaced apart from the door lintel. On closing of the door the door leaf is moved in the vertical sections, whereupon the guides are then pivoted by manual action toward the door opening such that the door leaf is pressed against a sealing assembly arranged there. This produces an air-tight closure.
A disadvantage of such lifting door systems is, however, that the sealing elements, at any rate in the lower region of the door opening, are still subject to considerable wear due to the door leaf sliding there along. Although the sealing elements do not wear off along their entire lengths, they still abrade distinctly in the lower region, so that no reliable sealing effect can be achieved there. Moreover, during the period of use of the lifting door systems with divided guide sections, the risk increases that a matching aligned connection between the lintel section and the vertical section can no longer be established. Then, a regular operation is no longer possible.
U.S. Pat. No. 1,869,347 finally discloses a lifting door arrangement in which, in the course of the closing movement of the door leaf, the vertical section of the guides is displaced parallel to the lintel section in the direction of the door opening. The displacing movement is initiated in that the door leaf meets, with its lower end shield that serves as a kind of trigger device here, the lower end of the vertical sections on both sides and takes them along for some distance up to the complete closing position due to the inherent weight of the door leaf. In this process, the vertical sections are each moved via an inclined connecting member guide both vertically and horizontally away from the assigned lintel section of the guides against a spring bias. The door leaf then rests on the frames of the door opening and establishes a more or less tight closure there. No sealing elements are apparently provided here. In the course of the opening movement the load at the lower end of the vertical sections on both sides finally ceases, so that they move back to their initial positions due to the spring bias and are in alignment with the lintel sections, so that the door leaf can be moved therein.
A disadvantage of this lifting door is that the door leaf performs a dragging movement at the frame elements of the door opening in the last portion of the closing movement. This results in considerable wear of the door leaf over the entire height thereof. Since a manual operation is apparently intended with this known lifting door, this is deemed to be acceptable due to the low movement speed. Such a lifting door is, however, not suited for fast-running operations.
Moreover, the spring assembly used for returning the vertical section is subject to substantial wear since it has to lift the inherent weight of the vertical section of the two guides during each opening movement. A particular problem is that, when the spring force decreases, there is no longer ensured that an aligned connection to the lintel section is reliably achieved. The door leaf can then no longer be moved into the lintel section without disruptions. The consequences of this are damages to the door leaf and problems during the operation of the lifting door.
It is therefore an object of the invention to further develop a generic lifting door such that it can be used with greater operational safety and at the same time improved sealing effect between the door leaf and the door opening.